The Data and Analysis Coordinating Center (DACC) for the Frequent Hemodialysis Clinical Trial Network (FHN) will coordinate the scientific and operational aspects of two clinical trials: one comparing short daily dialysis with conventional dialysis and one comparing long nocturnal dialysis with conventional dialysis. In the planning phase (Phase I), the DACC, in conjunction with the FHN, will design and develop the protocols and data forms for the two trials. A detailed proposal is suggested for one trial. Systems for data acquisition (via a secure web-based data entry) and data management will be established. The DACC will develop procedures for enhancing quality and completeness of the data collected. A detailed Manual of Operations will be developed describing the data collection procedures and other procedures for the Coordinating Clinical Centers (CCC) and their associated dialysis units. The DACC will provide centralized training of CCC staff on the entry of trial patients, the completion of trial forms, and the use of the data management system. A web site will be created for study information available to FHN investigators and a portion for public access. Central facilities will be established as necessary. The DACC will arrange and actively participate in meeting and conference calls of the Steering and Planning Committee and its subcommittees. A major function of the DACC during the Recruitment and Follow-Up (Phase II) of each trial will be to monitor patient recruitment and compliance as a whole and by CCC. The database management system developed in Phase I will be used to assure accurate and complete collection of trial data. An inquiry system will be used to resolve data discrepancies. Trial progress will be reported in reports to the CCC, Steering and Planning Committee, and External Advisory Committee. Statistical and interim analyses will be performed during the course of each trial with final analyses completed and reported in Phase II1. The DACC will develop new statistical methodology as needed to properly analyze the data being collected. Biological specimens and data will be transferred to repositories elsewhere as required. Since the FHN is a multi-centered effort on two trials, the DACC will provide leadership to coordinate the trial designs and conduct them to optimize the efficiency of the information gained. The DACC will work to foster a spirit of cooperation, which is important in this network.